Dipper went down the stairs. He had been having some very good personal time by reading ancient sumerian manuscripts he found on the Gravity Falls bank, and they told of wonderous and wise things about ancient akkadian civilisations.
"Ah, if only I could share this knowledge with the scientific community" he sighed, he really hoped to share his discoveries with the world and be immortalised as a god scientist emperor and get all the babes so he could make Wendy jealous for not letting him rape her.
But alas, such tomfoolery would have to wait. He went down the stairs because he was really thristy, all that reading of desert city texts had made him invision the wonderous waters of the Tigris and Euphrates and made him want to crave fig juice. So he walked right down the stairs and-
"JESUS CHRIST MABEL WHAT THE FUCK ARE YOU DOING!?"
Mabel Pines was laying on the floor, nude from the waist down, shoving her pet pig Waddles into her grostesquely engorged snatch, the poor animal kicking and screaming as most of his torso was within Mabel's hateful uterus, inflating her belly in a pig-shaped mound, her hands on the boar's arse and shoving him further into her vagina. Around her laid the mutilated corpses of goats, woodpeckers, crocodiles and children, the limbs hacked off and thrown together in a pile, while a massive goblet of gold laid beside her, full of filth and the blood of saints.
"Ah, just in time, Dipper my brother!" she moaned evilly and whoristically, "Watch as I transcend my pitiful existence and become the greatest of all calamities!"
And so she dipped (geddit) her fingers on Waddles' anus and covered them in bloody pig diarrhea, and wrote on her forehead "Babylon the Great, the Mother of Prostitutes and Abominations of the Earth", and licked and swallowed the remaining dung with much pleasure. With a final thrust, she shoved the rest of Waddles body up her canal, only his hindhoofs remaining outside. Her womb then began to constrict, and Waddles was slowly and painfully masticated to death, his internal organs and bones completly smashed and crushed within those fleshy halls, blood, viscerae, fat, bile and shit flowing forth from Mabel's vagina as the pig was destroyed. Mabel moaned with much hatred and pleasure and bobbed her head wildly like Animal in The Muppets movie, screaming in eldritch tongues obscenities against existence. In a few minutes, a massive pool of Waddles' fluids laid before her, and his bump inside her was drastically reduced, only a small hill that barely indicated there was a pig previously inside. With a final push, Waddles' hooves came inside, and the dead pig was completly within Mabel's uterus.
"Now Dipper my twin, I am pregnant with the messiah of darkness and despair, the greatest Beast that shall lay the world in ruin! You shall do as I say, or else there will be grave...CONSEQUENCES!"
Dipper could only whimper, he was completly horrorfied by the whimsical display of violence and suinophobia before him, and much disliked the way the children's bodies were arranged. If only he could rape Wendy to get his mind off this.
"Good, now take me to hospital so that I may give birth the the Prince of DEATH with dignity and uncomplications!" Mabel said, taking a sip from her goblet of holy blood and shit.
"B-but you only got preganted now!" cried Dipper fearfully and confusedly.
"Indeed, but I am the Whore Queen, my pregnancy only lasts as much as I desire!"
And to prove her point, her belly was now fully round like at the end of pregnancy. Evil, eldritch noises could be heard from within her, and the bulges of what appeared to be tentacles and hooves appeared on it. Screaming faces of children occasionally appeared, frozen in abstract suffering and terror. Dipper swallowed a gob of spit, and led the way to the car.
"I have to prevent my sister from birthing!" he thought secretly to himself, "I musn't let this abomination be born and ruin my chances to get revenge on Wendy!"
So Dipper drove the car, but through a thin road in the middle of the forest. Tons of gnomes, squirrels and school children were trampled to death by the wheels, their intestines rolling around the tires and spewing blood and shit everywhere. Mabel much liked, devouring the filth with much pleasure, but she got suspicious of Dipper.
"Brother, the road to the hospital is not here!" she hissed evilly like a dementia siren with congenital vaginitis and hateful pus globs of despise.
"Uh, this is a short cut to the hospital! I musn't make the baby wait!"
But Dipper...WAS LYING! He wasn't taking her to the hospital, he was taking her to the Gravity Falls ABORTION CLINIC! He had gone there many times to spy on Wendy having abortions, he secretly impregnated her in her sleep because abortion was his favourite fetish and he liked to inflict it on the woman he wanted to rape. So after a few minutes they arrived at a massive clearing with a large un-asphalted parking lot, full of red dust from fetus blood. The abortion clinic was a simple wooden building made of rotten wood that was falling apart, with huge flashing neon letters saying "GRAVITY FALLS ABORTION CLINIC: 100% DISCOUNT FOR NON-WHITE BABIES".
"Dipper, I don't think we're in the hospital" grunted Mabel.
"N-n-no Mabel we ARE in the hospital! The letters, they are out of order, so it's "Gravity Falls Hospital" spelled backwards!"
"Uh, no, backwards is SEIBAB ETIHW-NON ROF TNUOCSID %001: CINILC NOITROBA SLLAF YTIVARG-"
Just then, a huge flash of cancerous white light appeared, and out of it came an ugly looking perv man with green and gold clothes and stupid horn apparatuses on his helmet...LOKI!
"Mmm baby yeah fuck me!" moaned Loki whorily, humping the air like a Zeus ravaged Ganymede.
"...let's just go inside" Mabel concluded.
So the twins entered the devil and ugly building. Inside there was a small reception room, the seats were all mouldy and covered in fungi and lichens. Rats, lizards and centipedes run around everywhere, eating the remains of the previous abortions. A small flickering bulb illuminated the place, and in the reception cabin was an old man full of warts, tumours and abcesses oozing putrid necrotic pus, with broken glasses, blooshot eyes, rotten yellow teeth and wearing a dirty white lab coat full of diarrhea stains and brown trousers full of mould and obnoxious vomit.
"Good evening" he hissed devily, "I take your are our clients?"
"Yes, my sister is in desperate need of a... release..." said Dipper, chosing his euphemisms carefully.
"Ah, yes, I can see that" the devil man said, flickering his forked reptile tongue lustfully at Mabel, "Shall we go in?"
"My brother must come too, he must witness the triumph of darkness!" grinned Mabel satanically.
"Indeed, he shall do more than just watch..."
Dipper didn't like that implication one bit, but before he could protest the good Doctor opened the door to the operation room and Mabel grabbed his arm and dragged him there.
"My God, what have I done?" whimpered Dipper to himself in thought, "I should have never come to this clinic!"
The abortion operation room was in no better state than the rest of the building, all the equipments and machinery were severely rusty and dirty, the computer monitors were severely decayed and full of moss, and the tools were all embuded in blood and shit crust. Pools of stagnant, shitty water were spread all across the floor, and the only unruined and undamaged thing in the place were the two massive, hellish red lights that illuminated the room. The air was thick and humid, with a severe rotten stench that made Dipper gag and vomit his stomachal contents: french fries, burritos, elephant cum, undignified rotten nipples and oreos. Mabel eagerly sat on the operational chair, imediately taking out her pants and showing her cancerous, tumour-filled pussy, oozing black, oily blood and yolk-like fluids. Her labia were full of abcesses, while her clitoris was decaying and rotten.
"I'm not going to lie, this will hurt like a bitch" moaned the doctor, looking at her pussy with salivation in his mouth.
"Go forth. What is pain to a whore but her thrall of MADNESS!?" said Mabel wisely.
Dipper try to look away, incest was a line he would not cross. But in his endless misogyny and desire to rape women, he could not look away from his sister's rotten, but exceptionally virginal, vagina. As the machine approached the pussy and the serrated, shit encrusted blades touched the hatefully carcinogenic labia and bathed themselves in the putrid liquids, the animalistic sexuality instincts of a man began coursing through his veins... his heart began beating faster... his blood began to run more rapidly... his cheeks became rosier and blsuhing... his penis began TO ERECT! Not before long, he was a most morose drooling RETARD, his one inch prepubescent cock finding itself tight in his blue trousers and polka dot panties, which the hungry sexuality dick had sliped out of and was now touching the zipper, the beautiful soft penis head bruising against the cold, hard metal. So, with his mind shut off and his zoological drives in control, he took off his pants, revealing his sexual organ to the world, lacking no shame or publicity.
"I see you like pussy... OF YOUR OWN SISTER!?" cackled Mabel crudely.
Just then Dipper's mind snapped back to normal and he was feeling very ashamed, trying to cover his wonderous and hot man lavender fruit. But the doctor grabbed him and put him ON HIS CROTCH!
"Now you're going to see what a REAL man has!" said the doctor lustfully.
Dipper was terrified and tried to turn his head away, but the doctor zipped his pants, and revealed a huge, 17 inch cock, that he rubbed against Dipper's face, covering it in precum. Dipper was amazed, he never knew men were so attractive and sexy, and the doctor's strong, manly musk filled his nostrils with pure masculine pleasure and arousal. His penis darted like the mighty lance of Týr upon Fenrir's foul mouth, and he inhaled and savoured that fine man smell, filling his lungs like powerful clouds. And nothing until that point had felt more natural and right.
"Doctor, your wonderous phallus is very sexy in my face" moaned Dipper whoristically, rubbing his cheeks and nose against the powerful doctor erection.
Full of pleasure and desire, Dipper, licked the shaft, and the doctor moaned. He licked all over the underside, then he went down to the balls, inhaling that powerful odour as the pubic hairs brushed against his face, licking those tasty, huge, succulent bals, kissing them, wriggling them about with his tongue, sucking them. They were almost as big as his mouth, so he salivated a lot, and made them all the more delicious.
"Oh, my boy, you are the best ball sucker this side of Oregon, "moaned the doctor sexually.
Dipper felt very complimented, so he swiftly licked upwards until he reached the powerful penis head, and oh God was it amazing. The head was huge, almost a fourth of the penis, and so much more tasty than the balls, oozing with yummy precum that Dipper milked. The doctor was circumcised, his dick was a perfect fuck machine not designed to masturbate but to have someone else pleasure, and Dipper gladly took that role, licking the head all over. Dipper was so overwhelmed by lust that he could take it any longer, and began sucking on that wonderous penis of a scientific body, blowing on it like a baby on a rotten mother's teat with much fervor and passion, moaning into the cock and sending delicious slivers of pleasure up the doctor body. Even though Dipper had never sucked a dick before, he was amazing at it, not a single teeth touching the cock head and the tongue enveloping the underside perfectly.
"Oh, oh, that's amazing!" moaned the doctor, completly lost in reckless abandon.
Meanwhile, the machine began stretching Mabel's putrid hatchery of maggots she calls vagina. Because the vaginal walls were very rotten and decaying the endometrium was completly peeled off like banana skins, releasing gallons upon galoons of black, necrotic blood that mixed with the shit crusts of the blades. The cervix was completly closed off by a bundle of large, chartreuse pus filled cysts, so when the blades began opening it they completly burst, making the blood acquire a distinct greenish tone. Mabel was loving the pain, the sensation of her flesh being ripped apart was the most pleasurable she ever had.
"Oh, oh it's opening!" moaned Mabel like a castrated koala smashed by elephant foot pads of despondency and evil under Helios' harsh glare.
And indeed, it was. Her cervix was completly stretch, making her belly have a huge bulge that was as high as her legs, which aroused the doctor immensely. With Dipper sucking him off as he was, he couldn't hold it anymore.
"My love, I'm going to cum!"
And cum he did, completly emptying his balls on Dipper's mouth, who swallowed everything with much pleasure. He milked the doctor's cock completly, a perfect void where all the cum had gone. But he was unsatisfied, he needed to cum himself.
"Behold, my child is born! HAW HAW HAW!" laughed Mabel evilly.
"WHAT!? But I send you here to abort it, to kill!" cried Dipper.
"That was the plan ALL ALONG!" moaned Mabel hatefully, "I knew that if I went to the hospital the authorities would arrest me and kill my unborn child after following the trail of murdered saints, so I made it so you carried me to the abortion clinic where I'd be safe! Thank you so much, my brother!"
Crap! Dipper had unadvertedly been the architect of his own demise, had fallen into his sister's evil plan! Now the world would be doomed, and he'd never have a chance to take revenge against Wendy... so why did he find himself unable to care?
"By all the gods of Hell, he is beautiful!" said the doctor.
Dipper went to look. Between the machine blades was his nephew, a rapidly growing creature that looked like a satyr, with the body of a man but the hindlimbs of a goat, powerful horns, and tons of tentacles coming from the back. The creature continued to grow and grow, and within a few minutes it was a twelve year old boy like Dipper! He opened his icy blue eyes, and golden hair voered his head. Most important of all, he developed a wonderous matured set of genitalia, frozen in the state of puberty like Dipper, just like the rest of his body.
"Why, hello there, my sexuality uncle!" moaned the satyr boy lustfully, getting off the machine sexily like a prostitute.
Dipper got very horny, and the satyr boy winked, turning around and getting on all fours, twerking his beautful ASSSSSS! Dipper wasted no time, and positioned himself, grabbing his nephew's waist and pushing his penis inside. He was still covered by Mabel's rotten placenta fluids, so he didn't need lube. With a powerful thrust, Dipper was in, and fucked his nephew in wilderness abandon.
"Oh, oh, yes my uncle fuck me GOOD!" moaned the Antichrist, his own penis erect like a falcon upon pitiful pigeons.
His tentacles wriggled about, and all of them inserted themselves on Dipper's arse, double fucking him with much intensity and beauty. Dipper moaned like a mutated kangaroo upon a garden of wonderous lettuces and flowers, his prostate stimulated like never before by these wonderous tentacles. Nothing felt more right or pleasurable in the world.
"I'm going to cum!" moaned Dipper, and he did.
Both boys ejaculated with much pleasure, Dipper on his nephew's ass and the Antichrist on the ground, fertilising it with beautiful flowers of various colours. Soon the vegetation spread everywhere, destroying the abortion clinic and replacing it with untamed wilderness, the beauty of plants growing rapdily and consuming everything, of predatory birds hunting children and cutting them to pieces with their beaks. Mabel and the Doctor were completly destroyed by the plants, which filled their bodies and bursted out, spreading blood and bile everywhere, though quickly cleansed by the devouring roots. Only Dipper and his lover remained.
"That was amazing!" said Dipper, kissing his nephew in the lips.
"You were amazing" he said, his hands rubbing Dipper's back and grouping his ass.
And so the two lovers were forever united by a trail of passion and sexuable activities, as civilisation fell to the might of the wilds.